Gear shift control linkage of transmission

Description

[0001] The present invention relates to a gear shift control linkage system for a vehicular transmission, comprising:

a manually operable gear shift control lever having upper and lower ends, and a fulcrum intermediate between the upper end and the lower end,

support means for supporting said control lever, said support means comprising pivot bearing means for allowing said control lever to swing on the fulcrum, and

a control rod pivotally connected at one end with the lower end of said control lever and pivotally connected at the other end with a striking rod of the transmission for transmitting a movement of said control lever to the transmission, said control rod comprising two parts, a first half control rod on the control lever side and a second half control rod on the transmission side connected together end to end by a joint, said control rod being supported rotatably and-axially slidably at an intermediate portion between both ends by an arm formed in said support means.

[0002] In such a transmission system, the control rod is provided for transmitting a manual movement of the control lever to the transmission to accomplish a speed change. However, the control rod also transmits vibrations of the engine reversely from the transmission to the control lever and to the body of the vehicle. If a resonance is caused in the linkage by a vibration of the engine, the vibration is amplified and exerts more harmful influence.

[0003] The US-A-2 390 711 discloses a gear shift control linkage system of the type mentioned above, wherein the control rod consists of two halves connected together by a joint. This known linkage system is specifically adapted to those cases wherein the general construction of the vehicle requires to employ an angled control rod.

[0004] Although the feature of bisecting the control rod has an influence on the vibration transmission properties thereof, a bisected control rod has so far not been employed in cases where the control rod substantially extends in a straight line. In such cases, there has generally been employed a linkage system including only one control rod which is supported by a single support rod connected at a first end with the vehicle body and at a second end with the transmission housing, as is for instance shown in the FR-A-2 181 112 and as will be explained later with reference to figure 1 of the drawings.

[0005] It is an object of the present invention to provide a gear shift control linkage system of a vehicular transmission which is arranged to restrict vibrations transmitted from the engine to a control lever and the body of the vehicle, even in those cases where the control rod need not to be angled.

[0006] It is another object of the present invention to provide a gear shift control linkage system of a vehicular transmission which is arranged not to be excited to a resonance by vibrations of the engine.

[0007] According to the present invention, a gear shift control linkage system of the type mentioned above is characterized in that said first and second half control rods are both substantially straight from end to end and arranged substantially in a straight line, and that said support means comprises a support rod extending substantially along a straight line in parallel with the control rod from said pivot bearing means to the transmission and having a first end fixed to a first bracket which is connected with a vehicle body through a first elastic means and a second end pivotally connected with a housing of the transmission, said arm being fixed to said support rod.

[0008] In some cases, the support rod, to comprises two parts, a first half support rod on the control lever side and a second half support rod on the transmission side which are connected together end to end by a joint.

[0009] 

Fig. 1 is a schematic view of a conventional control linkage system for a transmission;

Fig. 2 is a schematic view showing one embodiment of the present invention;

Fig. 3 is a schematic view showing a second embodiment of the present invention;

Fig. 4 is a graphical representation showing the results of a vibration experiment;

Fig. 5 is a graphical representation showing the relationship between the natural frequency of a rod and the length of the rod.

[0010] To facilitate understanding the present invention, a brief reference will be made to an example of a conventional control linkage system for a transmission, depicted in Fig. 1. In Fig. 1, a control rod 1 is connected, at one end through a universal joint 4, with a striking rod 3 which extends into a transmission 2 connected with an engine (not shown). The control rod 1 extends rearward of the transmission 2 and is connected at the other end rotatably with a lower portion of a control or shift lever 5.

[0011] A support rod 6 is pivotally connected at one end through a pin (not shown) with the transmission 2. The support rod 6 extends rearward substantially in parallel with the control rod 1 and is fixed to a bracket 7 which is connected with a vehicle body member 9 through an elastic member 8. The support rod 6 swingably supports the control lever 5 through a spherical bearing 10. Thus, the control lever 5 is swingable in the fore and aft direction (right and left in Fig. 1) and in the right and left direction (perpendicular to the plane of the paper in Fig. 1).

[0012] When a knob 5a on the top end of the control lever 5 is moved right and left, the control lever 5 swings right and left on the spherical bearing 10, which causes the control rod 1 to rotate to effect a so-called select operation. When the knob 5a is then moved fore and aft, the control lever 5 swings fore and aft on the spherical bearing 10, which causes the control rod 1 to move axially to effect a so-called shift operation. Thus, a gear change is accomplished in the transmission 2.

[0013] In this control linkage system for a transmission, the length of the control rod 1 is determined by the relation of the positions of the transmission 2 and the control lever 5. Therefore, it is difficult to avoid a resonance of the control rod 1 which occurs when the frequency of a vibration caused by the engine revolution coincides with the natural frequency of the control rod 1. Such a resonance amplifies the vibration of the engine, which is then transmitted through the control rod 1 not only to the control lever but also to the vehicle body via the support portion of the control rod 1.

[0014] In view of the above description, a reference is now made to embodiments of the present invention shown in Figs. 2 and 3.

[0015] In Fig. 2, a control rod 1 is divided into two parts, a first part 1 a on the control lever side and a second part 1b on the transmission side, and these two parts 1a and 1b are connected together by a universal joint 11. This control rod 1 is connected at one end with a striking rod 3 of a transmission 2 through a universal joint 4. The control rod 1 extends rearward of the transmission 2, and the other end of the control rod 1 is rotatably connected with a lower portion of a control lever 5, as in the case of Fig. 1.

[0016] One end of a support rod 6 is swingably connected with the transmission 2 by a pin. The support rod 6 extends substantially in parallel with the control rod 1 and is fixed at the other end with a bracket which is connected with a vehicle body 9 through an elastic member 8. The support rod 6 swingably supports the control lever 5 through a spherical bearing 10. Thus, the control lever 5 is swingable in the fore and aft or shift direction (right and left in Fig. 2) and in the right and left or select direction (normal to the plane of the paper in Fig. 2). The spherical bearing 10 comprises a spherical seat 10a formed in the support rod 6 and a ball portion 10b which is formed in the control rod 5 and confined in the spherical seat 10a.

[0017] The support rod 6 is integrally formed with an arm 12 extending toward the control rod 1. This arm 12 of the support rod 6 has at an end a support portion 13 which supports the first part 1a a of the control rod 1. The support portion 13 of the arm 12 comprises a spherical seat 13a, and a ball member 13b confined in the spherical seat 13a. The ball member 13b has a hole extending from one side to the opposite side through the center of the ball member. The first part 1 a of the control rod 1 extends through the hole of the ball member 13b. Thus, the first part 1a is axially movable by sliding along the inner surface of the hole of the ball member 13b, and rotatable by the aid of the spherical contact between the spherical seat 13a and the ball member 13b and the cylindrical surface contact between the first part 1a of the control rod 1 and the hole of the ball member 13b.

[0018] In general, engines are normally operated only within an engine speed range up to about 6000 rpm, and therefore it is practically important to reduce vibrations of the control lever 5 within this speed range. It is also to be noted that the vibration of an engine mainly comprises a vertical component. This vertical component is transmitted to the control rod 1 and the support rod 6 and causes a transverse vibration of a rod in each rod.

[0019] In general, the natural frequency fc of a transverse vibration of a rod is related to the length I of the rod. This relationship is expressed by

where A is the sectional area of the rod, E its modulus of longitudinal elasticity, p its density, J its second moment of inertia. This is graphically shown in Fig. 5.

[0020] If the lengths of the control rod 1 and the support rod 6 are both determined as being about 680 mm (the length of a single control rod and a single support rod used in the linkage of Fig. 1), then the natural frequencies of the rods 1 and 6 are both about 120 Hz. Accordingly, the vibration of the engine operated within the normal speed range can approach to the natural frequency of the rods with the results of a resonance in both the rods 1 and 6.

[0021] If, on the other hand, the length of a rod is 400 mm, the natural frequency of this rod is 400 Hz as is evident from the above mentioned equation and Fig. 5. The engine rotational speed corresponding to this frequency, 400 Hz, is much higher than the normal engine speed range. Therefore, a resonance of the rod is prevented within the normal engine speed range, and the vibration of the control lever is reduced.

[0022] The control linkage of Fig. 2 is operated as follows: When the control lever 5 is moved in the select direction, the first part 1 a of the control rod 1 rotates about a straight line passing through the center of the spherical bearing 10 and the center of the support portion 13, and the second part 1 b of tme control rod 1 rotates about its own axis. When the control lever 5 is moved in the shift direction, both of the first part 1 a and the second part 1 b of the control rod 1 axially move back and forth, and this movement is transmitted to the striking rod 3 for accomplishing a speed change.

[0023] A second embodiment of the present invention is shown in Fig. 3. In this embodiment, the support rod 6, too, is divided into two parts. A first part 6a of the support rod 6 on the control lever side is connected with a second part 6b on the transmission side by a universal joint 16. A bracket 17 is fixed to the second part 6b of the support rod 6 on the transmission side, and is connected to the vehicle body member 9 through an elastic member 15. In this embodiment, the second part 1b of the control rod 1 is supported by the support portion 13 of the arm 12 integral with the second part 6b of the support rod 6. The end of the second part 6b of the support rod on the transmission side is pivotally connected with the transmission 2 as in the case of the first embodiment.

[0024] The results of an experiment on vibration of the control lever 5 of the embodiment of Fig. 3 are shown in Fig. 4. In Fig. 4, a broken line a shows a vibration characteristic in the case of a conventional linkage using a single control rod and a single support rod. A solid line b shows a vibration characteristic in the case of this embodiment. As is evident from Fig. 4, the vibration of the control lever 5 is significant reduced within the normal engine speed range-(-6000 rpm).

Claims

1. A gear shift control linkage system for a vehicular transmission, comprising:

a manually operable gear shift control lever (5) having upper and lower ends, and a fulcrum intermediate between the upper end and the lower end,

support means (6) for supporting said control lever, said support means comprising pivot bearing means (10) following said control lever to swing on the fulcrum, and

a control rod (1) pivotally connected at one end with the lower end of said control lever and pivotally connected at the other end with a striking rod (3) of the transmission (2) for transmitting a movement of said control lever to the transmission, said control rod comprising two parts, a first half control rod (1a) on the control lever side and a second half control rod (1b) on the transmission side connected together end to end by a joint (11), said control rod being supported rotatably and axially slidably at an intermediate portion between both ends by an arm (12) formed in said support means,

characterized in that

said first and second half control rods (1a, 1b) are both substantially straight from end to end and arranged substantially in a straight line, and that said support means comprises a support rod (6) extending substantially -along a straight line in parallel with the control rod (1) from said pivot bearing means (10) to the transmission (2) and having a first end fixed to a first bracket (7) which is connected with a vehicle body through a first elastic means (8), and a second end pivotally connected with a housing of the transmission (2), said arm (12) being fixed to said support rod (6).

2. A gear shift control linkage system according to claim 1, characterized by that said arm has, at an end, a slide bearing means (13) which supports rotatably and axially slidably said half control rod (1a) on the control lever side.

3. A gear shift control linkage system according to claim 2, characterized by that said support rod is divided into a first half support rod (6a) on the control lever side and a second half support rod (6b) on the transmission side connected together end to end by a joint (16), an intermediate portion of said support rod between said first and second ends being fixed to a second bracket (17) which is connected to the vehicle body through a second elastic means (15), said first and second half support rods being arranged substantially in a straight line.

4. A gear shift control linkage system according to claim 3, characterized by that said second bracket (17) is fixed to said second half support rod (6b), said arm (12) being fixed to said second bracket, said arm having, at an end, a slide bearing means (13) which supports rotatably and axially slidably said second half control rod on the transmission side.

Ansprüche

1. Schaltgestänge für Fahrzeug - Wechselgetriebe mit:

- einem von Hand betätigbaren Schalthebel (5) mit oberen und unteren Enden und einem Drehpunkt zwischen den oberen und unteren Enden,

- einer Stützeinrichtung (6) zur Abstützung des Schalthebels, welche Stützeinrichtung gelenkige Lagermittel (10) umfaßt, die eine Schwenkbewegung des Schalthebels um den Drehpunkt gestatten, und

-einer Steuerstange (1), die an einem Ende gekenkig mit dem unteren Ende des Schalthebels und am anderen Ende gelenkig mit einer Schaltstange (3) des Wechselgetriebes (2) verbunden ist, so daß die Bewegung des Schalthebels zu dem Wechselgetriebe übertragen wird, welche Steuerstange zwei Teile, nämlich eine erste Steuerstangenhälfte (1a) auf der Seite des Schalthebels und eine zweite Steuerstangenhälfte (1b) auf der Seite des Wchselgetriebes umfaßt, die durch ein Gelenk (11) endweise miteinander verbunden sind, wobei die Steuerstange in einem mittleren Abschnitt zwischen beiden Enden durch einen an der Stützeinrichtung ausgebildeten Arm (12) drehbar und axial verschiebbar gehalten ist,
dadurch gekennzeichnet, daß

- die ersten und zweiten Steuerstangenhälften (1a, 1b) beide im wesentlichen geradlinig von einem Ende bis zum anderen ausgebildet und im wesentlichen in einer geraden Linie ausgerichtet sind und

- daß die Stützeinrichtung eine im wesentlichen längs einer geraden Linie parallel zu der Steuerstange (1) von den Lagermitteln (10) zu dem Wechselgetriebe (2) verlaufende Stützstange (6) umfaßt, deren erstes Ende an einer ersten Halterung (7) befestigt ist, die mit dem Fahrzeugaufbau über eine erste elastische Einrichtung (8) verbunden ist, und deren zweites Ende gelenkig mit einem Gehäuse des Wechselgetriebes (2) verbunden ist, wobei der Arm (12) an der Stützstange (6) befestigt ist.

2. Schaltgestänge nach Anspruch 1, dadurch gekennzeichnet, daß der Arm an einem Ende ein Gleitlager (13) aufweist, das die schalthebelseitige Steuerstangenhälfte (1 a) drehbar und axial verschiebbar abstützt.

3. Schaltgestänge nach Anspruch 2, dadurch gekennzeichnet, daß die Stützstange in eine erste Stützstangenhälfte (6a) auf der Seite des Schalthebels und eine zweite Stützstangenhälfte (6b) auf der Seite des Wechselgetreebes unterteilt ist, welche beide Hälften durch ein Gelenk (16) endweise miteinander verbunden sind, daß ein mittlere Abschnitt der Stützstange zwischen den ersten und zweiten Enden an einer zweiten Halterung (17) befestigt ist, die mit dem Fahrzeugaufbau über eine zweite elastische Einrichtung (15) verbunden ist, und daß die ersten und zweiten Stützstangenhälften im wesentlichen in einer geraden Linie angeordnet sind.

4. Schaltgestänge nach Anspruch 3, dadurch gekennzeichnet, daß die zweite Halterung (17) an der zweiten Stützstangenhälfte (6b) befestigt ist und daß der Arm (12) an der zweiten Halterung befestigt ist und an einem Ende ein Gleitlager (13) aufweist, das die getriebeseitige zweite Steuerstangenhälfte drehbar und axial verschiebbar abstützt.

Revendications

1. Système de tringlerie d'une commande de changement de vitesse pour une transmission d'un véhicule, comprenant:

un levier de commande de changement de vitesse (5) à actionnement manuel ayant des extrémités supérieure et inférieure et un point de pivot entre l'extrémité supérieure et l'extrémité inférieure,

un moyen de support (6) pour supporter ledit levier de commande, ledit moyen de support comprenant un moyen de support de pivot (10) pour permettre audit levier de commande de pivoter sur le point de pivot, et

une tige de commande (1) reliée pivotante à une extrémité à l'extrémité inférieure dudit levier de commande et reliée pivotante à son autre extrémité à une tige d'embrayage (3) de la transmission (2) pour transmettre un mouvement dudit levier de commande à la transmission, ladite tige de commande comprenant deux parties, une première moitié de tige de commande (1a) du côté levier de commande et une seconde moitié de tige de commande (1 b) du côté transmission reliées ensemble bout à bout par une jointure (11), ladite tige de commande étant supportée rotative et axialement coulissante en une partie intermédiaire entre les deux extrémités par un bras (12) formé dans ledit moyen de support,
caractérisé en ce que

lesdites première et seconde moitiés de tige de commande (1a, 1b) sont toutes deux sensiblement droites d'une extrémité à l'autre et agencées sensiblement en ligne droite, et

que ledit moyen de support comprend une tige de support (6) s'étendant sensiblement le long d'une ligne droite parallèlement à la tige de commande (1) à partir dudit moyen de support de pivot (10) jusqu'a la transmission (2) et ayant une première extrémité fixée à une première patte (7) qui est reliée à une carrosserie du véhicule par un premier moyen élastique (8) et une seconde extrémité reliée pivotante à un carter de la transmission (2), ledit bras (12) étant fixé à ladite tige de support (6).

2. Système de tringlerie de commande de changement de vitesse selon la revendication 1 caractérisé en ce que ledit bras a, à une extrémité, un moyen formant palier coulissant (13) qui supporte de manière rotative et axialement coulissante ladite moitié de tige de commande (1a) du côté levier de commande.

3. Système de tringlerie de commande de changement de vitesse selon la revendication 2 caractérisé en ce que ladite tige de support est divisée en une première moitié de tige de support (6a) du côté levier de commande et une seconde moitié de tige de support (6b) du côté transmission reliées l'une à l'autre bout à bout par une jointure (16), une partie intermédiaire de ladite tige de support entre lesdites première et seconde extrémités étant fixée à une seconde patte (17) qui est reliée à la carrosserie du véhicule par un second moyen élastique (15), lesdites première et seconde moitiés de tiges de support étant agencées sensiblement en ligne droite.

4. Système de tringlerie de commande de changement de vitesse selon la revendication 3 caractérisé en ce que ladite seconde patte (17) est fixée à ladite seconde moitié de tige de support (6b), ledit bras (12) étant fixé à ladite seconde patte, ledit bras ayant, à une extrémité, un organe formant palier coulissant (13) qui supporte de manière rotative et axialement coulissante ladite seconde moitié de tige de commande du côté transmission.

Drawing